Field of the Invention
The present invention relates to a torque limiting and conical braking assembly for a power winch, and more particularly to the torque limiting and ratcheted brake assembly capable of timely cutting off the power whenever the reverse torque produced by a carrying load exceeds the bearable torque of the power supply while producing a conical braking effect, so as to prevent the power winch from being damaged by a transmission mechanism.
Description of the Related Art
Power winch is a device designed for hanging or dragging a load. For example, a hoist is a common application of the power winch, and a cable winch installed at the front of a jeep or a cross-country vehicle for trailing another car (to help others) or moving out of danger (to rescue oneself) is another common application of the power winch. The principle of operating the power winch is to output a forward or reverse transmission power by a power supply (such as a power motor) and acted by a reduction mechanism to drive a cable wheel to rotate in a forward or reverse direction to release or retrieve a cable, and a load (such as a heavy object, another car, or another object) is hooked by a heavy-duty hook installed at a front end of the cable, so as to move the load conveniently.
Since the winch carries a load (such as goods, objects, or people waiting to be rescued), and the load sometimes exceeds the torque bearable by the power supply (which involves the loading capacity of the power supply), therefore a torque limit mechanism with an overload protection is generally installed in a transmission mechanism for preventing any torque produced by the load and unbearable by the power supply, such that if an overload occurs, the torque limit mechanism will rotate idly and slip and will no longer transmit power, so as to protect the transmission mechanism (such as a power motor, a reduction mechanism, etc) of the power winch, and prevent the components of the power winch from being damaged by the overload. In the meantime, an unpowered braking mechanism is further installed in the transmission mechanism for stopping a power transmission process immediately whenever the power winch is unpowered (by pressing a stop button or by a power failure), so as to protect the transmission mechanism from being damaged.
However, the torque limit mechanism and the unpowered braking mechanism of a conventional power winch are designed as two separate devices. For example, a conventional current breaker is used as the torque limit mechanism such that when the torque of the load increases, the current of the power supply current also increases. Therefore, the power of the power supply will be disconnected when there is an overload of current, so as to provide the effect of limiting the torque indirectly; and a conventional electromagnetic brake clutch is used as the unpowered braking mechanism, and both current breaker and electromagnetic brake mechanism are installed at different positions of the transmission process of the power winch, and thus doubling the cost, causing unsmooth operation (when the compatibility of the two mechanisms is low), and/or even damaging the components over a long time of use.
Besides the use of the current breaker as the torque limit mechanism and the use of the electromagnetic brake clutch as the unpowered brake mechanism by the power winch, the winch power cannot be used at all during power failure. In addition, it takes a buffer time for the current breaker and the electromagnetic brake clutch to be turned on and off, and an immediate effect cannot be achieved. Therefore, the power transmission of the power winch cannot be disconnected and the power winch cannot be stopped immediately when an overload occurs. Obviously, the practicality of the conventional power winch requires improvements.